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Related papers: On the properties of quasi-Banach function spaces

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In this survey, we discuss the definition of a (quasi-)Banach function space. We advertise the original definition by Zaanen and Luxemburg, which does not have various issues introduced by other, subsequent definitions. Moreover, we prove…

Functional Analysis · Mathematics 2024-05-31 Emiel Lorist , Zoe Nieraeth

We give necessary and sufficient conditions for a real-valued quasiconvex function f on a Baire topological vector space X (in particular, Banach or Frechet space) to be continuous at the points of a residual subset of X. These conditions…

Optimization and Control · Mathematics 2015-01-20 Patrick J. Rabier

This paper explores some important aspects of the theory of rearrangement-invariant quasi-Banach function spaces. We focus on two main topics. Firstly, we prove an analogue of the Luxemburg representation theorem for rearrangement-invariant…

Functional Analysis · Mathematics 2025-10-15 Anna Musilová , Aleš Nekvinda , Dalimil Peša , Hana Turčinová

In classical analysis, the relationship between continuity and Riemann integrability is an intimate one: a continuous function on a closed and bounded interval is always Riemann integrable whereas a Riemann integrable function is continuous…

Functional Analysis · Mathematics 2016-12-05 M. A. Sofi

We introduce a new class of quasi-Banach spaces as an extension of the classical Grand Lebesgue Spaces for small values of the parameter, and we investigate some its properties, in particular, completeness, fundamental function, operators…

Functional Analysis · Mathematics 2020-08-07 Maria Rosaria Formica , Eugeny Ostrovsky , Leonid Sirota

In this paper, we prove the boundedness of multilinear fractional integral operators from products of Hardy spaces associated with ball quasi-Banach function spaces into their corresponding ball quasi-Banach function spaces. As…

Functional Analysis · Mathematics 2025-04-01 Jian Tan

We give a new proof of a characterization of the closeness of the range of a continuous linear operator and of the closeness of the sum of two closed vector subspaces of a Banach space. Then we state sufficient conditions for the closeness…

Functional Analysis · Mathematics 2015-10-06 Joël Blot , Philippe Cieutat

In this paper we prove off-diagonal, limited range, multilinear, vector-valued, and two-weight versions of the Rubio de Francia extrapolation theorem in general quasi-Banach function spaces. We prove mapping properties of the generalization…

Classical Analysis and ODEs · Mathematics 2024-09-16 Zoe Nieraeth

In 1994, M. M. Popov [On integrability in F-spaces, Studia Math. no 3, 205-220] showed that the fundamental theorem of calculus fails, in general, for functions mapping from a compact interval of the real line into the lp-spaces for 0<p<1,…

Functional Analysis · Mathematics 2013-08-29 Fernando Albiac , Jose L Ansorena

This paper provides a self-contained exposition of coorbit spaces associated to integrable group representations and quasi-Banach function spaces, and at the same time extends and simplifies previous work. The main results provide an…

Functional Analysis · Mathematics 2024-02-26 Jordy Timo van Velthoven , Felix Voigtlaender

The Hahn-Banach theorem is an extension theorem for linear functionals which preserves certain properties. Specifically, if a linear functional is defined on a subspace of a real vector space which is dominated by a sublinear functional on…

Functional Analysis · Mathematics 2016-11-09 A. T. Diab , S. I. Nada , D. L. Fearnley

In this paper, we investigate the boundedness of composition operators defined on a quasi-Banach space continuously included in the space of smooth functions on a manifold. We prove that the boundedness of a composition operator strongly…

Functional Analysis · Mathematics 2023-05-04 Isao Ishikawa

We present a sufficient condition for a Banach space to have the approximate hyperplane series property (AHSP) which actually covers all known examples. We use this property to get a stability result to vector-valued spaces of integrable…

Functional Analysis · Mathematics 2017-04-25 Yun Sung Choi , Sun Kwang Kim , Han Ju Lee , Miguel Martín

In this paper, we study spaceability of subsets of generalized Orlicz and Lebesgue spaces associated to Banach function space. Also, we give some sufficient conditions for spaceability of subsets of a general Banach space which improves an…

Functional Analysis · Mathematics 2022-08-09 Alireza Bagheri Salec , Stefan Ivkovic , Seyyed Mohammad Tabatabaie

We present some results related to Hahn-Banach extension theorem for linear operators on asymmetric normed spaces. L. Nachbin, Trans. Amer. Math. Soc. 68 (1950), proved that a Banach space has the extension property for linear operators (a…

Functional Analysis · Mathematics 2024-12-17 S. Cobzaş

There are two main aims of the paper. The first one is to extend the criterion for the precompactness of sets in Banach function spaces to the setting of quasi-Banach function spaces. The second one is to extend the criterion for the…

Functional Analysis · Mathematics 2017-01-11 António Caetano , Amiran Gogatishvili , Bohumír Opic

This survey aims to highlight some of the consequences that representable (and continuous) functionals have in the framework of Banach quasi *-algebras. In particular, we look at the link between the notions of *-semisimplicity and full…

Functional Analysis · Mathematics 2020-02-21 Maria Stella Adamo

This paper presents a necessary and sufficient condition for a real-valued function defined on an open and convex subset of a Banach space to be quasi-concave, and a sufficient condition for such a function to be strictly quasi-concave.…

Optimization and Control · Mathematics 2023-02-15 Yuhki Hosoya

A map f between two metric spaces (X,d_1) and (Y,d_2) is called a coarse embedding of X into Y if there exist two nondecreasing functions phi_1, phi_2:[0,\infty) --> [0,\infty) such that: phi_1(d_1(x,y)) \leq d_2(f(x),f(y)) \leq…

Functional Analysis · Mathematics 2007-05-23 N. L. Randrianarivony

In the study of locally convex quasi *-algebras an important role is played by representable linear functionals; i.e., functionals which allow a GNS-construction. This paper is mainly devoted to the study of the continuity of representable…

Functional Analysis · Mathematics 2017-06-14 Maria Stella Adamo , Camillo Trapani
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